The East Greenland Coastal Current: Its Structure, Variability and Large-Scale Impact

David Sutherland, Ph.D., 2008
Robert Pickart, Advisor

The subtidal circulation of the southeast Greenland shelf is described using a set of high-resolution hydrographic and velocity transects occupied in summer 2004. The main feature present is the East Greenland Coastal Current (EGCC), a low-salinity, high-velocity jet with a wedge-shaped hydrographic structure. The EGCC was observed along the entire shelf south of Denmark Strait, which when combined with evidence from chemical tracer measurements, implies the EGCC contains a significant Pacific Water signal, suggesting that the EGCC is an inner branch of the polar-origin East Greenland Current (EGC). A set of idealized laboratory experiments supported this hypothesis, showing that for a range of oceanic parameters, a buoyant current like the EGC could potentially influence EGCC formation. The volume transport of the combined EGC/EGCC system is roughly constant (~2 Sv) from 68°N to Cape Farewell, while the corresponding freshwater transport increases by ~60% over this distance (59 to 96 mSv). This trend is explained by constructing a simple freshwater budget of the EGCC/EGC system that accounts for meltwater runoff, melting sea-ice and icebergs, and net precipitation minus evaporation. Variability on interannual timescales is examined by calculating the Pacific Water content in the EGC/EGCC from 1984-2004 in the vicinity of Denmark Strait.